The presented dataset contains information on the distribution and species composition of zooplankton (rotifers and crustaceans) registered in the Basin of the Middle Volga River. Russia. The studies have been performed in the Kuibyshev Reservoir (Samara Oblast and the Republic of Tatarstan). the Saratov Reservoir (Samara Oblast). https://www.roneverhart.com/Mizuno-Prospect-GXC105-Youth-Catcher-s-Mitt/